N2 - When ultrafast noncritical cascaded second-harmonic generation
of energetic femtosecond pulses occur in a bulk lithium niobate crystal
optical Cherenkov waves are formed in the near- to mid-IR. Numerical
simulations show that the few-cycle solitons radiate Cherenkov (dispersive)
waves in the λ = 2.2−4.5 μm range when pumping at λ1 = 1.2−1.8 μm.
The exact phase-matching point depends on the soliton wavelength, and
we show that a simple longpass filter can separate the Cherenkov waves
from the solitons. The Cherenkov waves are born few-cycle with an
excellent Gaussian pulse shape, and the conversion efficiency is up to 25%.
Thus, optical Cherenkov waves formed with cascaded nonlinearities could
become an efficient source of energetic near- to mid-IR few-cycle pulses.

AB - When ultrafast noncritical cascaded second-harmonic generation
of energetic femtosecond pulses occur in a bulk lithium niobate crystal
optical Cherenkov waves are formed in the near- to mid-IR. Numerical
simulations show that the few-cycle solitons radiate Cherenkov (dispersive)
waves in the λ = 2.2−4.5 μm range when pumping at λ1 = 1.2−1.8 μm.
The exact phase-matching point depends on the soliton wavelength, and
we show that a simple longpass filter can separate the Cherenkov waves
from the solitons. The Cherenkov waves are born few-cycle with an
excellent Gaussian pulse shape, and the conversion efficiency is up to 25%.
Thus, optical Cherenkov waves formed with cascaded nonlinearities could
become an efficient source of energetic near- to mid-IR few-cycle pulses.